CANNED FISHERY PRODUCTS 



313 



What is heat processing? From the standpoint of processing require- 

 ments, foods may be divided into two categories: the ''acid" foods (pH 

 below 4.5) and the ''low acid" foods (pH 4.5 and above) i. While the spores 

 of food spoilage bacteria may be easily destroyed in acid foods because of 

 the effect of pH, similar spores in the low acid foods require substantially 

 greater heat treatment to render them harmless. Since the heat resistance 



SEAMING PANEL 



SEAMING PANEL RADIUS 



CURL 



SEALING COMPOUND 



CHUCK WALL RADIUS 



SEAMING PANEL 



SEAUNG COMPOUND 



SEAMING WALL 

 RADIUS 



BODY HOOK 

 RADIUS 



SEAMING WALL 



BODY HOOK 



END HOOK 



END HOOK RADIUS 



SEAMING PANEL RADIUS 



CHUCK WALL 



BODY WALL 



CHUCK WALL RADIUS 



Figure 24.2. End unit and double seam terminology. {Continental 

 Can Co., Inc). 



of food spoilage bacteria varies widely, it is necessary first to determine 

 the thermal death time or the lethality necessary to destroy the spores in 

 question. It is then necessary, in order to determine the process (time and 

 temperature of cook necessary to render the product in question commer- 

 cially sterile), to measure the rate of heat penetration into the slowest 

 heating portion of the container of food. The rate of heat penetration is 

 determined by inserting thermocouples into the container of food and 



